Add/Subtract Days

Add or subtract days, weeks, months or years from any date — right in your browser. Pick a start date (it defaults to today), type how many days, weeks, months or years to move, choose add or subtract, and the resulting date appears instantly with its full spelling, its day of the week, and an ISO 8601 string you can copy. It’s the answer to questions like “what is 45 days from today?”, “what date is 6 weeks from now?” or “what was the date 90 days ago?” Unlike the one-answer pages that only handle a single number, this tool lets you change the start date, the amount, the unit and the direction live, and it handles the tricky calendar cases correctly: adding a month to January 31 lands on the last day of February, and leap years are counted exactly. Nothing is uploaded — the calculation runs entirely on your device.

How it works

1. Choose a start date — it starts on today, but you can pick any date.
2. Type the amount and choose the unit: days, weeks, months or years.
3. Pick Add to move forward in time, or Subtract to move backward.
4. Read the resulting date and its day of the week, and copy the ISO 8601 string if you need it.

FAQ